Jennifer M. Wright

Injectable loop recorder implantation in an ambulatory setting by advanced practice providers: Analysis of outcomes

Implantable loop recorder (ILR) insertion has historically been performed in a surgical environment such as the electrophysiology (EP) lab. The newest generation loop recorder (Medtronic Reveal LINQ™, Minneapolis, MN, USA) is injectable with potential for implantation in a non‐EP lab setting by advanced practice providers (APPs) facilitating improved workflow and resource utilization. We report the safety and efficacy of injectable ILR placement in the ambulatory care setting by APPs.

Two cases of supraventricular tachycardia after accessory pathway ablation.

A 52-year-old man was referred for recurrent palpitations after 2 prior electrophysiology studies and ablations at an outside institution targeting right anteroseptal and left posterolateral accessory pathways (AP) for orthodromic reentrant tachycardia (ORT). Baseline ECG revealed sinus rhythm without preexcitation and an incomplete right bundle branch block. An ECG from his most recent tachycardia episode demonstrated a long RP tachycardia, with an incomplete right bundle branch block pattern at a rate of 135 beats per minute. Prior echocardiogram showed no evidence of structural heart disease. At electrophysiology study, the baseline atrial-His (AH) and His-ventricular (HV) intervals were both 58 ms. There was no preexcitation with incremental atrial pacing. There were spontaneous echo beats, which had a ventriculoatrial (VA) interval of 230 ms with concentric-appearing retrograde activation. Tachycardia with a cycle length (CL) of 460 ms was reproducibly initiated with programmed ventricular stimulation after a retrograde VA jump. Entrainment from the right ventricle (RV; mid-septum) showed a V-A-V response and a postpacing interval (PPI) of 583 ms without significant AH prolongation (Figure 1). Stim-A minus V-A time was 97 ms. Premature ventricular complexes (PVCs) from the septum during tachycardia advanced the atrium only if they were delivered ≥45 ms before the His deflection. Differential pacing was performed with entrainment from the RV apex yielding a PPI of 605 ms, whereas RV basal pacing resulted in a PPI of 601 ms. PPI from the proximalcoronary sinus (CS) was markedly prolonged (>50 ms over tachycardia CL) and was even longer from the mid CS (Figure 2). Mapping of the annular septum showed earliest retrograde activation at the mid right atrial (RA) septum. PPI with entrainment from here was 20 ms >tachycardia CL. What is the mechanism of the tachycardia, and what is the appropriate next step? Figure 1. Response to entrainment from the mid-right ventricular …

P‐Wave Amplitude and PR Changes in Patients With Inappropriate Sinus Tachycardia: Findings Supportive of a Central Mechanism

Background The mechanism of inappropriate sinus tachycardia (IST) remains incompletely understood. Methods and Results We prospectively compared 3 patient groups: 11 patients with IST (IST Group), 9 control patients administered isoproterenol (Isuprel Group), and 15 patients with cristae terminalis atrial tachycardia (AT Group). P‐wave amplitude in lead II and PR interval were measured at a lower and higher heart rate (HR1 and HR2, respectively). P‐wave amplitude increased significantly with the increase in HR in the IST Group (0.16±0.07 mV at HR1=97±12 beats per minute versus 0.21±0.08 mV at HR2=135±21 beats per minute, P=0.001). The average increase in P‐wave amplitude in the IST Group was similar to the Isuprel Group (P=0.26). PR interval significantly shortened with the increases in HR in the IST Group (146±15 ms at HR1 versus 128±16 ms at HR2, P<0.001). A similar decrease in the PR interval was noted in the Isuprel Group (P=0.6). In contrast, patients in the atrial tachycardia Group experienced PR lengthening during atrial tachycardia when compared with baseline normal sinus rhythm (153±25 ms at HR1=78±17 beats per minute versus 179±29 ms at HR2=140±28 beats per minute, P<0.01). Conclusions We have shown that HR increases in patients with IST were associated with an increase in P‐wave amplitude in lead II and PR shortening similar to what is seen in healthy controls following isoproterenol infusion. The increase in P‐wave amplitude and absence of PR lengthening in IST support an extrinsic mechanism consistent with a state of sympatho‐excitation with cephalic shift in sinus node activation and enhanced atrioventricular nodal conduction.

Antiarrhythmic drugs in pregnancy

The risk of arrhythmia development or recurrence is increased during pregnancy. For those arrhythmias that are unresponsive to conservative therapy, such as vagal maneuvers or life style interventions, or that present a higher risk to the mother or fetus, medical therapy may be necessary. In each case, the patient and provider must carefully consider the risks and benefits of a particular therapy. This requires an understanding of the data regarding the safety and efficacy of any particular drug, which in some cases may be extensive and in others quite limited. Fortunately, options exist for the treatment of arrhythmias during pregnancy.